Organic geochemistry

Organic geochemistry is the study of the impacts and processes that organisms have had on the Earth. It is mainly concerned with the composition and mode of origin of organic matter in rocks and in bodies of water. The study of organic geochemistry is traced to the work of Alfred E. Treibs, "the father of organic geochemistry." Treibs first isolated metalloporphyrins (derivatives of hemes, etc.) from petroleum. This discovery established the biological origin of petroleum, which was previously poorly understood. Metalloporphyrins in general are highly stable organic compounds, and the detailed structures of the extracted derivatives made clear that they originated from chlorophyll. But the field, as such, didn't really develop until the latter half of the twentieth century, when natural products chemists began trying to understand and track the transformations of natural products produced by organisms over geologic time--in marine sediments, rocks, oil, and coal. This led to development of ever-more-sophisticated and sensitive methods of spectroscopic analysis. Early applications included trying to identify the first traces of microbial life on earth in ancient rocks and ascertaining whether there were any signs of past or present life in the first samples of Lunar dust, as well as exploration for new petroleum deposits.